Magnetoresistive memory device assemblies, and methods of forming magnetoresistive memory device assemblies

ABSTRACT

The invention includes a construction comprising an MRAM device between a pair of conductive lines. Each of the conductive lines can generate a magnetic field encompassing at least a portion of the MRAM device. Each of the conductive lines is surrounded on three sides by magnetic material to concentrate the magnetic fields generated by the conductive lines at the MRAM device. The invention also includes a method of forming an assembly containing MRAM devices. A plurality of MRAM devices are formed over a substrate. An electrically conductive material is formed over the MRAM devices, and patterned into a plurality of lines. The lines are in a one-to-one correspondence with the MRAM devices and are spaced from one another. After the conductive material is patterned into lines, a magnetic material is formed to extend over the lines and within spaces between the lines.

RELATED PATENT DATA

This patent resulted from a continuation application of U.S. patentapplication Ser. No. 10/920,740, which was filed on Aug. 17, 2004 nowU.S. Pat. No. 7,032,286; which in turn resulted from a continuationapplication of U.S. patent application Ser. No. 10/302,187, which wasfiled on Nov. 21, 2002, and which issued as U.S. Pat. No. 6,781,174 onAug. 24, 2004; which is a divisional application of U.S. patentapplication Ser. No. 10/165,352, which was filed on Jun. 6, 2002 nowU.S. Pat. No. 6,780,653; all of the above-listed patent applications arehereby incorporated by reference.

TECHNICAL FIELD

The invention pertains to methods of forming magnetoresistive memorydevices, and to methods of forming assemblies comprisingmagnetoresistive memory devices, such as, for example, methods offorming MRAM arrays. The invention also pertains to assembliescomprising magnetoresistive memory devices, such as, for example, MRAMarrays.

BACKGROUND OF THE INVENTION

Magnetic random access memory (MRAM) devices are showing increasingpromise for utilization as memory storage devices of the future. MRAM isa type of digital memory in which digital bits of information comprisealternative states of magnetization of magnetic materials in memorycells. The magnetic materials can be thin ferromagnetic films.Information can be stored and retrieved from the memory devices byinductive sensing to determine a magnetization state of the devices, orby magnetoresistive sensing of the magnetization states of the devices.It is noted that the term “magnetoresistive device” can be utilized tocharacterize a memory device and not the access device, and accordinglya magnetoresistive device can be accessed by, for example, eitherinductive sensing or magnetoresistive sensing methodologies.

A significant amount of research is currently being invested in magneticdigital memories, such as, for example, MRAM's, because such memoriesare seen to have significant potential advantages relative to thedynamic random access memory (DRAM) components and static random accessmemory (SRAM) components that are presently in widespread use. Forinstance, a problem with DRAM is that it relies on electric chargestorage within capacitors. Such capacitors leak electric charge, andmust be refreshed at approximately 64-128 millisecond intervals. Theconstant refreshing of DRAM devices can drain energy from batteriesutilized to power the devices, and can lead to problems with lost datasince information stored in the DRAM devices is lost when power to thedevices is shutdown.

SRAM devices can avoid some of the problems associated with DRAMdevices, in that SRAM devices do not require constant refreshing.Further, SRAM devices are typically faster than DRAM devices. However,SRAM devices take up more semiconductor real estate than do DRAMdevices. As continuing efforts are made to increase the density ofmemory devices, semiconductor real estate becomes increasingly valuable.Accordingly, SRAM technologies are difficult to incorporate as standardmemory devices in memory arrays.

MRAM devices have the potential to alleviate the problems associatedwith DRAM devices and SRAM devices. Specifically, MRAM devices do notrequire constant refreshing, but instead store data in stable magneticstates. Further, the data stored in MRAM devices will remain within thedevices even if power to the devices is shutdown or lost. Additionally,MRAM devices can potentially be formed to utilize less than or equal tothe amount of semiconductor real estate associated with DRAM devices,and can accordingly potentially be more economical to incorporate intolarge memory arrays than are SRAM devices.

Although MRAM devices have potential to be utilized as digital memorydevices, they are currently not widely utilized. Several problemsassociated with MRAM technologies remain to be addressed. It would bedesirable to develop improved methods for operation of MRAM devices.

FIG. 1 illustrates a fragment of an exemplary prior art construction 10comprising an MRAM device 12. More specifically, construction 10comprises a substrate 14 having a conductive line 16 formed thereover,and device 12 is formed over the conductive line.

Substrate 14 can comprise an insulative material, such as, for example,borophosphosilicate glass (BPSG), silicon dioxide and/or siliconnitride. Such insulative material can be formed over a semiconductivematerial, such as, for example, monocrystalline silicon. Further,various integrated circuit devices can be supported by thesemiconductive material. In the construction of FIG. 1, substrate 14 isillustrated generically as a homogeneous mass, but it is to beunderstood from the discussion above that substrate 14 can comprisenumerous materials and layers. In the event that substrate 14 comprisesa semiconductive material, such semiconductive material can be, forexample, monocrystalline silicon lightly-doped with a background p-typedopant. To aid in interpretation of the claims that follow, the terms“semiconductive substrate” and “semiconductor substrate” are defined tomean any construction comprising semiconductive material, including, butnot limited to, bulk semiconductive materials such as a semiconductivewafer (either alone or in assemblies comprising other materialsthereon), and semiconductive material layers (either alone or inassemblies comprising other materials). The term “substrate” refers toany supporting structure, including, but not limited to, thesemiconductive substrates described above.

Conductive line 16 can comprise, for example, various metals and metalalloys, such as, for example, copper and/or aluminum.

The MRAM device 12 formed over line 16 comprises three primary layers,18, 20 and 22. Layers 18 and 22 comprise soft magnetic materials, suchas, for example, materials comprising one or more of nickel, iron,cobalt, iridium, manganese, platinum and ruthenium. Layers 18 and 22 canbe the same composition as one another, or different from one another.

Layer 20 comprises a non-magnetic material. The non-magnetic materialcan be an electrically conductive material (such as copper) inapplications in which the MRAM is to be a giant magnetoresistive (GMR)device, or can be an electrically insulative material (such as, forexample, aluminum oxide (Al₂O₃) or silicon dioxide), in applications inwhich the MRAM device is to be a tunnel magnetoresistive (TMR) device.

Layers 18 and 22 have magnetic moments associated therewith. Themagnetic moment in layer 18 is illustrated by arrows 19, and themagnetic moment in layer 22 is illustrated by arrows 21. In the shownconstruction, the magnetic moment in layer 22 is anti-parallel to themagnetic moment in layer 18. Such is one of two stable orientations forthe magnetic moment of layer 22 relative to that of 18, with the otherstable orientation being a parallel orientation of the magnetic momentin layer 22 relative to the moment in layer 18. One of layers 18 and 22can have a pinned orientation of the magnetic moment therein, and suchcan be accomplished by providing a hard magnetic layer, or in otherwords a permanent magnet (not shown) adjacent the layer. The layerhaving the pinned magnetic moment can be referred to as a referencelayer.

In operation, MRAM device 12 can store information as a relativeorientation of the magnetic moment in layer 22 to that in layer 18.Specifically, either the anti-parallel or parallel orientation of themagnetic moments of layers 18 and 22 can be designated as a 0, and theother of the anti-parallel and parallel orientations can be designatedas a 1. Accordingly, a data bit can be stored within device 12 as therelative orientation of magnetic moments in layers 18 and 22.

A conductive line 24 is shown over layer 22, and such conductive lineextends into and out of the plane of the page. Conductive line 24 cancomprise, for example, one or more metals and/or metal alloys,including, for example, copper and/or aluminum.

An insulative material 26 extends over conductive line 16, and along thesides of bit 12 and conductive line 24. Insulative material 26 cancomprise, for example, BPSG.

The construction 10 is an exemplary MRAM construction, and it is to beunderstood that various modifications can be made to the construction 10for various applications. For instance, one or more electricallyinsulative layers (not shown) can be provided between device 12 and oneor both of conductive lines 16 and 24. Also, one or more magnetic layers(not shown) can be stacked within device 12 in addition to the shownlayers 18 and 22.

In operation, data is written to MRAM device 12 by passing current alongthe conductive lines 16 and 24 to change the relative magneticorientation of layers 18 and 22 (i.e., to flip the relative orientationfrom parallel to anti-parallel, or vice versa). In theory, the relativeorientation of layers 18 and 22 can be flipped by passing sufficientcurrent along only one of lines 16 and 24, but in practice it isgenerally found to be advantageous to utilize both of lines 16 and 24 inwriting information to device 12. Specifically, some current isinitially passed along one of the lines 16 and 24 to induce a magneticfield in device 12 which starts to flip the relative magneticorientation of layers 18 and 22, and then current is passed along theother of layers 16 and 24 to complete the flip of the relative magneticorientation within device 12.

The operation of reading information from device 12 can utilize eitherinductive sensing or magnetoresistive sensing to detect the relativemagnetic orientation of layers 18 and 22 within the device. The readingcan utilize one or both of lines 16 and 24, and/or can utilize aseparate conductive line (not shown).

It is advantageous to have lines 16 and 24 be orthogonal to one anotherat the location of device 12 to maximize the complementary effect ofutilizing both of conductive lines 16 and 24. A device which utilizes apair of independently controlled conductive lines for writing to and/orreading from an MRAM device is typically referred to as a half-selectMRAM construction.

As discussed above, a single MRAM device can store a single bit ofinformation. Accordingly, in applications in which it is desired toprocess multiple bits of information it is generally desired to utilizea plurality of MRAM devices, with each of the devices independentlystoring bits of information. The devices will typically be arranged inan array, and an exemplary array 50 of MRAM devices is illustrated inFIG. 2. More specifically, FIG. 2 shows a top view of an arraycomprising the construction 10 of FIG. 1. The array comprises a firstset of conductive lines 24, 52, 54 and 56 within the insulative material26; and a second set of conductive lines 16, 58 and 60. The second setof conductive lines is shown as dashed-lines to indicate that the secondset of conductive lines is beneath the insulative material 26 and firstset of conductive lines. Individual MRAM devices (not visible in theview FIG. 2) are at crossings of the first and second sets of conductivelines, with the locations of the devices being designated by labels 10,64, 66, 68, 70, 72, 74, 76, 78, 80, 82, and 84. The various MRAM devicesof the array would typically be fabricated identically to one another,and accordingly can all be identical to the device 12 described in FIG.1.

Problems can be encountered during operation of an MRAM array ifrelatively large currents are utilized in the first and/or second setsof conductive lines during reading from and/or writing to MRAM devices.Accordingly, it would be desirable to develop methods for reducing theamount of current flow utilized in conductive lines associated with theMRAM array during reading and/or writing operations.

SUMMARY OF THE INVENTION

In one aspect, the invention encompasses a method of forming amagnetoresistive memory device assembly. A plurality of memory devicesare formed to be supported by a substrate. The memory devices are spacedfrom one another. Each of the memory devices comprises a non-magneticcomposition between a pair of magnetic compositions. An electricallyconductive material is formed over the memory devices. The conductivematerial is patterned into a plurality of lines. The lines are inone-to-one correspondence with the memory devices and are spaced fromone another. After the conductive material is patterned into lines, amagnetic material is formed over the lines. The magnetic materialextends into spaces between the lines.

In one aspect, the invention encompasses a method of forming an MRAMassembly. A substrate is provided, and the substrate comprises a firstelectrically conductive line and a plurality of memory devices over thefirst line. Memory devices are spaced from one another by gaps, and thememory devices comprise a non-magnetic composition between a pair ofmagnetic compositions. A mass is formed over the memory devices.Openings are formed to extend through the mass and to the memorydevices. An electrically conductive material is formed within theopenings, and the electrically conductive material within the openingsdefines second electrically conductive lines over the memory devices.The second lines cross the first line at the memory devices. At leastsome of the mass is removed from between the second lines to formopenings. A magnetic material is formed over the second lines. Themagnetic material extends into the openings between the second lines.

In one aspect, the invention includes an MRAM construction. An MRAMdevice is between a pair of conductive lines. Each of the conductivelines can generate a magnetic field encompassing at least a portion ofthe MRAM device. Each of the conductive lines is surrounded on threesides by magnetic material to concentrate the magnetic fields generatedby the conductive lines at the MRAM device.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the invention are described below withreference to the following accompanying drawings.

FIG. 1 is a diagrammatic, cross-sectional view of a fragmentillustrating a prior art MRAM construction.

FIG. 2 is a diagrammatic illustration of a top view of an arraycomprising the MRAM construction of FIG. 1.

FIG. 3 is a diagrammatic, cross-sectional view of a fragment at apreliminary processing stage of an exemplary method of an aspect of thepresent invention.

FIG. 4 is a view of the FIG. 3 fragment shown at a processing stagesubsequent to that of FIG. 3.

FIG. 5 is a view of the FIG. 3 fragment shown at a processing stagesubsequent to that of FIG. 4.

FIG. 6 is a view of the FIG. 3 fragment shown at a processing stagesubsequent to that of FIG. 5.

FIG. 7 is a view of the FIG. 3 fragment shown at a processing stagesubsequent to that of FIG. 6.

FIG. 8 is a view of the FIG. 3 fragment shown at a processing stagesubsequent to that of FIG. 7.

FIG. 9 is a view of the FIG. 3 fragment shown at a processing stagesubsequent to that of FIG. 6, in accordance with an alternative aspectof the invention relative to that described in FIGS. 7 and 8.

FIG. 10 is a view of the FIG. 3 fragment shown at a processing stagesubsequent to that of FIG. 6 in accordance with another alternativeaspect of the invention.

FIG. 11 is a view of the FIG. 3 fragment shown at a processing stagesubsequent to that of FIG. 10.

FIG. 12 is a view of the FIG. 3 fragment shown at a processing stagesubsequent to that of FIG. 5 in accordance with yet another alternativeaspect of the invention.

FIG. 13 is a diagrammatic, cross-sectional view of a fragment of an MRAMassembly at a preliminary processing stage of another aspect of theinvention.

FIG. 14 is a view of the FIG. 13 fragment shown at a processing stagesubsequent to that of FIG. 13.

FIG. 15 is a view of the FIG. 13 fragment shown at a processing stagesubsequent to that of FIG. 14.

FIG. 16 is a diagrammatic, top view of an MRAM assembly illustrating afurther aspect of the invention.

FIG. 17 is a diagrammatic, cross-sectional view along the line 17-17 ofFIG. 16.

FIG. 18 is a diagrammatic, cross-sectional view along the line 18-18 ofFIG. 16.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A first exemplary aspect of the invention is described with reference toFIGS. 3-8. Similar numbering will be used in referring to FIGS. 3-8 aswas utilized above in describing prior art FIGS. 1 and 2, whereappropriate.

Referring initially to FIG. 3, a construction 100 is shown incross-sectional view. Construction 100 is illustrated at a preliminaryprocessing step in a method of forming a magnetoresistive memory deviceassembly, such as, for example, an MRAM array.

Construction 100 comprises a substrate 14 supporting a conductive line16. It is noted that in accordance with the definition of “substrate”provided in the background section of this disclosure, portion 14 alonecan be considered a substrate, or alternatively, portion 14 andconductive line 16 together can be considered a substrate.

MRAM device locations 10, 70, 76 and 82 are defined over conductive line16, and MRAM devices 12, 102, 104 and 106 are formed in the locations.The MRAM devices can be considered memory devices. Each of the memorydevices comprises a non-magnetic composition (or mass) 20 between a pairof magnetic compositions (or masses) 18 and 22. The memory devicescomprise upper surfaces 107, and sidewall surfaces 108.

Memory devices 12, 102, 104 and 106 are separated by spaces (or gaps)110, 112 and 114. Accordingly, the memory devices are spaced from oneanother.

A mass 116 is formed over conductive line 16, and openings 118, 120, 122and 124 extend through the mass to upper surfaces 107 of memory devices12, 102,104 and 106. Mass 116 can comprise, for example, an electricallyinsulative material, such as one or more of borophosphosilicate glass(BPSG), silicon dioxide and silicon nitride. In exemplary aspects of theinvention, mass 116 can initially be formed to extend across the memorydevices, and subsequently openings 118, 120, 122 and 124 can be formedwithin the mass. The openings can be formed by, for example, initiallyproviding a patterned mask (not shown) over mass 116, and then extendinga pattern of the mask into mass 116 to form the openings. The patternedmask can comprise, for example, photoresist, and a pattern within themask can be formed by, for example, photolithographic processing.Openings 118, 120, 122 and 124 are complimentary to lines (discussedbelow) which are ultimately formed within the openings.

Referring to FIG. 4, an electrically conductive material (or mass) 130is provided over mass 116 and within openings 118, 120, 122 and 124(FIG. 3). Conductive material 130 can comprise, for example, variousmetals or metal alloys, and in particular aspects can comprise one orboth of copper and aluminum. Conductive material 130 is formed overmemory devices 12, 102, 104 and 106, and in the shown embodimentphysically contacts upper surfaces 107 of the devices. It is to beunderstood, however, that the invention can encompass other aspects (notshown) wherein an insulative or other material is provided overuppermost surfaces 107 prior to forming conductive material 130.

Mass 116 comprises an uppermost surface 117, and in the shown aspect ofthe invention, conductive material 130 is formed over uppermost surface117.

Referring to FIG. 5, construction 100 is subjected to planarization(such as, for example, chemical-mechanical polishing) to form aplanarized upper surface 132, and to remove material 130 from overuppermost surface 117 of mass 116. Planarized surface 132 is showncoextensive with uppermost surface 117 of mass 116. It is to beunderstood, however, that the planarization can remove portions of mass116, in addition to removing conductive material 130 from over mass 116.Accordingly, the uppermost surface 117 of FIG. 5 can be at a lowerelevational level than the uppermost surface 117 of FIG. 4. The material130 remaining in the construction 100 of FIG. 5 forms lines 24, 52, 54and 56. The lines are in a one-to-one correspondence with memory devices12, 102, 104 and 106. Further, the lines are spaced from one another bygaps coextensive with the gaps 110, 112 and 114 between the memorydevices. The lines have top surfaces 141, and side surfaces 143 (withthe top and side surfaces being labeled for only one of the lines).

Referring to FIG. 6, some of mass 116 is removed from within gaps 110,112 and 114, and such reduces an elevational level of the mass withinthe gaps. In the shown aspect of the invention, a portion of theinsulative mass 116 has been removed from between the conductive lines,but the insulative mass has not been removed from between the memorydevices. The portion of mass 116 remaining within gaps 110, 112 and 114is thicker than an elevational thickness of memory devices 12, 102, 104and 106. Accordingly, the remaining portions of mass 116 entirely coversidewalls 108 (FIG. 3) of the memory devices. Although portions of mass116 remain within gaps 110, 112 and 114 in the shown aspect of theinvention, it is to be understood that an entirety of mass 116 can beremoved from within the gaps in other aspects of the invention(discussed below). The removal of some or all of mass 116 can beaccomplished with either a dry or wet etch.

The reduction in thickness of mass 116 exposes sidewalls 143 of lines24, 52, 54 and 56.

Referring to FIG. 7, a dielectric material 150 is formed over conductivelines 24, 52, 54 and 56, as well as across upper surfaces of mass 116within gaps 110, 112 and 114. Dielectric material 150 is formed as acontinuous expanse extending along sidewall surfaces 143 and topsurfaces 141 of conductive lines 24, 52, 54 and 56, as well as over thesubstrate 14 within the spaces 110, 112 and 114 between the conductivelines. The dielectric material can comprise, for example, one or more ofsilicon dioxide, silicon nitride and aluminum oxide; and can be formedto a thickness of, for example, from about 100 Å to about 200 Å. Thedielectric material can be formed by, for example, chemical vapordeposition.

A magnetic material 152 is formed over dielectric material 150. Themagnetic material extends over lines 24, 52, 54 and 56, and into thespaces 110, 112 and 114 between the lines. In the shown application, themagnetic material is, like the dielectric material, formed to be acontinuous expanse extending along sidewall surfaces and top surfaces oflines, as well as over the substrate within spaces between the lines.The magnetic material can comprise a thickness of, for example, fromabout 50 Å to about 100 Å, and can comprise various ferromagneticmaterials. In particular aspects, the magnetic material comprises one ormore of iron, nickel and cobalt. The magnetic material can be formed byany of various deposition processes, including, for example, physicalvapor deposition. An exemplary physical vapor deposition process issputter deposition.

The magnetic material 152 can, in particular aspects, be considered acladding around conductive lines 24, 52, 54 and 56. The cladding canconcentrate magnetic fields formed by current passing through theconductive lines, and specifically can concentrate the magnetic fieldswithin memory devices 12, 102, 104 and 106. Referring to line 24 andmemory device 12 as an example, the magnetic field (or moment) inducedat device 12 by current flow through line 24 can be enhanced by thecladding of magnetic material 152 relative to the magnetic field thatwould result from the same amount of current in the absence of thecladding. For instance, if it is desired to obtain a magnetic field ofabout 50 oersteds at memory device 12, a current of from about 2milliamps to about 3 milliamps would typically be flowed through theconductive line 24 to induce the desired magnetic field. However, thepresence of magnetic material 152 can enable a current flow of only 1milliamp to be sufficient to induce the desired 50 oersteds at memorydevice 12. Accordingly, methodology of the present invention can enablea lower amount of current to be flowed through conductive linesproximate MRAM devices, while still producing desired magnetic fields atthe devices. Such reduction in current flow can alleviate problemsassociated with prior art MRAM arrays.

Referring to FIG. 8, an insulative mass 160 is provided over magneticmaterial 152. Mass 160 comprises an upper surface 161 which can beplanarized. Subsequently, additional devices (not shown) can be formedover such upper surface.

The processing described above with reference to FIGS. 3-8 is but oneexample of processing that can be utilized to form a magnetic materialaround lines associated with an MRAM array. FIG. 9 illustrates anotherexemplary process. Specifically, FIG. 9 illustrates the construction 100at a processing step subsequent to FIG. 7, and illustrates that segmentsof magnetic material 152 and dielectric material 150 have been removedfrom within the gaps 110, 112 and 114 between lines 24, 52, 54 and 56.However, the dielectric material 150 and conductive material 152 remainalong sidewall and top surfaces of the conductive lines 24, 52, 54 and56. Accordingly, the magnetic material 152 remains around peripheries ofthe conductive lines in an orientation where it can direct magneticfields generated by current passing through the conductive linesdownwardly toward memory devices beneath the conductive lines. Insubsequent processing, (not shown) an insulative material (such as thematerial 160 of FIG. 8) can be formed over the conductive lines andacross the gaps between the conductive lines.

Another aspect of the invention is described with reference to FIGS. 10and 11. In referring to FIGS. 10 and 11, similar numbering will be usedas was utilized above in describing FIGS. 3-8, where appropriate.

Referring to FIG. 10, a construction 200 is illustrated at a processingstep subsequent to FIG. 6. Magnetic material 152 is formed over lines24, 52, 54 and 56. The magnetic material extends along sidewall and topsurfaces of the lines, and further extends across gaps 110, 112 and 114between the lines. The construction 200 of FIG. 10 is shown at a similarprocessing step to the construction 100 of FIG. 7, but differs from theconstruction 100 of FIG. 7 in that the dielectric material 150 (FIG. 7)is not provided in the construction 200.

A patterned mask 202 is formed over portions of magnetic material 152associated with conductive lines 24, 52, 54 and 56 while leavingportions of magnetic material 152 within gaps 110, 112 and 114 exposed.Patterned mask 202 can comprise, for example, photoresist, and can bepatterned utilizing photolithographic processing.

Referring to FIG. 11, exposed portions of magnetic material 152 areremoved from within gaps 110, 112 and 114, and subsequently mask 202(FIG. 10) is removed. The magnetic material 152 remaining is alongsidewalls 143 and top surfaces 141 of lines 24, 52, 54 and 56. Further,magnetic material 152 is physically against such sidewall and topsurfaces of the lines. It is preferred that magnetic material 152 doesnot contact either of the magnetic compositions 18 and 22 of memorydevices 12, 102, 104 and 106. The insulative material 116 previouslyformed within gaps 110, 112 and 114 prevents magnetic material 152 fromphysically contacting the magnetic compositions of the memory devices.

The removal of exposed portions of magnetic material 152 to form theshown pattern in FIG. 11 can be considered as transferring a patternfrom mask 202 to the underlying conductive material 152.

Another aspect of the invention is described with reference to FIG. 12.In describing FIG. 12 similar numbering will be used as was utilizedabove in describing FIGS. 3-8, where appropriate. FIG. 12 illustrates aconstruction 300 shown at a processing step subsequent to that of FIG.5. Specifically, the insulative mass 116 (FIG. 5) has been entirelyremoved from within gaps 110, 112 and 114, and subsequently dielectricmaterial 150 and magnetic material 152 are formed. The dielectricmaterial 150 prevents magnetic material 152 from physically contactingmagnetic compositions 18 and 22 of memory devices 12, 102, 104 and 106.In subsequent processing (not shown) one or both of magnetic material152 and dielectric material 150 can be removed from within gaps 110, 112and 114. Alternatively, materials 150 and 152 can be left within gaps110, 112 and 114 in completed devices formed in accordance with themethodology of FIG. 12.

FIGS. 13-15 illustrate another aspect of the invention. In referring toFIGS. 13-15 similar numbering will be used as was utilized above indescribing the embodiment of FIGS. 3-8, where appropriate. FIG. 13illustrates a construction 400 comprising substrate 14, conductive line16, and memory devices 12, 102, 104 and 106. Electrically conductivematerial 130 is formed over memory devices 12, 102, 104 and 106, as wellas within gaps 110, 112 and 114 between the devices.

Referring to FIG. 14, an upper surface of material 130 is planarized toform a planar upper surface 401. The planarization can be accomplishedby, for example, chemical-mechanical polishing. A patterned mask 402 isformed over planar surface 401. Mask 402 can comprise, for example,photoresist and can be patterned utilizing photolithographic processing.Mask 402 comprises portions over memory devices 12, 102, 104 and 106.Gaps 404 are between the portions of mask 402, and conductive material130 is exposed within such gaps. Gaps 404 are over the spaces 110, 112and 114 between memory devices 12, 102, 104 and 106.

68 Referring to FIG. 15, a pattern is transferred from mask 402 (FIG.14) to conductive material 130, and subsequently mask 402 is removed.The transferring of the pattern from mask 402 to material 130 results inportions of conductive material exposed within openings 404 (FIG. 14)being removed. The conductive material 130 remaining at the processingstage of FIG. 15 is in the form of lines 24, 52, 54 and 56. Insubsequent processing (not shown) an insulative material can be providedbetween memory devices 12, 102, 104 and 106 to form a layer analogous tothe layer 116 of FIG. 6. Subsequently, any of the processing describedabove with references to FIGS. 7-11 can be conducted to form the variousconstructions showing FIGS. 7-11. Alternatively, the dielectric material150 and magnetic material 152 (discussed above) can be provided overlines 24, 52, 54 and 56, as well as within spaces between the lines togenerate a construction analogous to that shown in FIG. 12.

The conductive lines 24, 52, 54 and 56 discussed above with referencesto various of FIGS. 3-15 can have a same type of relative configurationas that shown in the array of FIG. 2, and further the conductive line 16of FIGS. 3-15 can have the same type of configuration as that shown inthe array of FIG. 2. Accordingly, lines 24, 52, 54 and 56 can beconsidered to cross line 16 at locations corresponding to memory devices12, 102,104 and 106. Additionally, lines 24, 52, 54 and 56 can extendalong directions that are primarily parallel to one another, and furthercan extend along directions which are substantially orthogonal to thedirection along which conductive line 16 extends. The term“substantially orthogonal” is utilized to indicate that lines 24, 52, 54and 56 can be orthogonal relative to line 16 within tolerances offabrication and measurement, which can be different than “orthogonal” isunderstood in an absolute mathematical sense.

The magnetic material 152 (see, for example, FIGS. 8, 9, 11 and 12) canbe considered to be a three-sided magnetic flux concentrator conductorwhich concentrates a magnetic field within an adjacent memory device.Various methods have been developed for providing magnetic fluxconcentrators around a bottom line associated with magnetoresistivedevices (see, for example, U.S. Pat. No. 5,956,267). The presentinvention provides a method for forming flux concentrators around thetop lines associated with an MRAM array. Methodology of the presentinvention can be utilized in combination with the prior art methodologyto form MRAM arrays in which flux concentrators are provided around bothbottom and top lines. It is considered that if flux concentrators areprovided on three sides of bottom lines, and also on three sides of toplines, the magnetic field induced by current flow through the top andbottom lines can be increased by at least two times relative to acurrent flow which would exist in the absence of the flux concentrators,and possibly by four times, or even more than four times, relative tothe magnetic field that would be induced in the absence of the fluxconcentrators.

FIGS. 16-18 illustrate an aspect of the invention in which fluxconcentrators are provided around opposing lines (such as bottom and toplines) associated with a half-select MRAM device. Similar numbering willbe utilized in referring to FIGS. 16-18 as was used in describing theconstructions of FIGS. 3-15, where appropriate.

Referring to FIG. 16, a construction 500 is illustrated in top view.Construction 500 comprises a substrate 502 and a pair of lineconstructions 504 and 506 supported by the substrate. The lines cross atan MRAM device (not visible in the view of FIG. 16).

Referring to the cross-sectional views of FIGS. 17 and 18, the MRAMdevice between the line constructions is visible as a device 12. Device12 comprises a pair of magnetic compositions (18 and 22) separated by anon-magnetic composition (20). Device 12 can be part of an MRAM array.

An electrically insulative mass 116 is along sidewalls of device 12, andline construction 504 is over the mass 116. Line construction 504comprises a conductive line 24 having an outer periphery 510. Line 24 issurrounded on three sides by dielectric material 150 and magneticmaterial 152. In particular aspects, magnetic material 152 can beconsidered to surround a portion, and only a portion, of outer periphery510 of line 24. Although magnetic material 152 is shown extendingentirely across the sides of line 24, it is to be understood that themagnetic material can, in alternative aspects of the invention, extendonly partially along the sides of line 24. Also, although line 24 isshown having a rectangular cross-sectional shape across an end of theline (see FIG. 18), and to accordingly have four sides to outerperiphery 510, it is to be understood that line 24 can have othershapes.

Device 12 is over line construction 506. Line construction 506 comprisesa conductive line 16 having an outer periphery 512. Line 16 issurrounded on three sides by a magnetic material 508. Line construction506 can be formed by, for example, methodology described in U.S. Pat.No. 5,956,267. In particular aspects, magnetic material 508 can beconsidered to surround a portion, and only a portion, of outer periphery512 of line 16. Although magnetic material 508 is shown extendingentirely across the sides of line 16, it is to be understood that themagnetic material can, in alternative aspects of the invention, extendonly partially along the sides of line 16. Also, although line 16 isshown having a rectangular cross-sectional shape across an end of theline (see FIG. 17), and to accordingly have four sides to outerperiphery 512, it is to be understood that line 16 can have othershapes.

Magnetic material 508 can be identical in composition to magneticmaterial 152, or different. In particular aspects, both of magneticmaterials 508 and 152 will comprise one or more of Fe, Ni and Co.

In compliance with the statute, the invention has been described inlanguage more or less specific as to structural and methodical features.It is to be understood, however, that the invention is not limited tothe specific features shown and described, since the means hereindisclosed comprise preferred forms of putting the invention into effect.The invention is, therefore, claimed in any of its forms ormodifications within the proper scope of the appended claimsappropriately interpreted in accordance with the doctrine ofequivalents.

1. A magnetoresistive memory array, comprising: a plurality of memorycells, individual memory cells including a non-magnetic compositionbetween a pair of magnetic compositions; first electrically conductivecontacts on first sides of the individual memory cells; the firstelectrically conductive contacts being configured to generate firstmagnetic fields overlapping at least portions of the individual memorycells when current is passed through the first electrically conductivecontacts; first magnetic material located outwardly of the firstelectrically conductive contacts and configured to concentrate the firstmagnetic fields; second electrically conductive contacts located onopposite sides of the individual memory cells to the first sides; thesecond electrically conductive contacts being configured to generatesecond magnetic fields overlapping at least portions of the individualmemory cells when current is passed through the second electricallyconductive contacts; and second magnetic material outwardly of thesecond electrically conductive contacts and configured to concentratethe second magnetic fields.
 2. The array of claim 1 wherein the firstelectrically conductive contacts are one or more lines comprisingrectangular cross-sectional shapes; wherein outer peripheries of the oneor more lines extend along four sides of the rectangular cross-sectionalshapes; and wherein the first magnetic material associated with a lineextends entirely along three of the four sides.
 3. The array of claim 1wherein the first electrically conductive contacts are one or more linescomprising rectangular cross-sectional shapes; wherein outer peripheriesof the one or more lines extend along four sides of the rectangularcross-sectional shapes; and wherein the first magnetic materialassociated with a line extends entirely along one of the four sides, andextends only partially along two other of the four sides.
 4. The arrayof claim 1 wherein the second electrically conductive contact are one ormore lines comprising rectangular cross-sectional shapes; wherein outerperipheries of the one or more lines extend along four sides of therectangular cross-sectional shapes; and wherein the second magneticmaterial associated with a line extends entirely along three of the foursides.
 5. The structure of claim 1 wherein the first and second magneticmaterials both comprise one or more of Fe, Ni and Co.
 6. The structureof claim 1 wherein the first and second magnetic materials are identicalin composition relative to one another.
 7. The structure of claim 1wherein the first and second magnetic materials are different incomposition relative to one another.